Xen devel - Dec 2005 - Dirtied pages in Xen''s shadow page tables

Hi All,
    I am trying to come up with a matrix that gives the information about the
Xen''s pages that are frequently dirtied. For this, I am going to use
the shadow page tables. In [unstable]/arch/x86/mm.c, it is mentioned that these
is a reference counting of pages and each page has two refcounts: tot_count and
type_count(line No. 29 to 45).
    But I didnt found these two refcounts being used anywhere else in the code.
Can anybody please tell me where I can find this information or guide me in
appropriate direction.
Thank you very much for your time and consideration. It will be a great help to
me,

Neeta.


_______________________________________________
Xen-devel mailing list
Xen-devel@lists.xensource.com
http://lists.xensource.com/xen-devel

xen-devel-bounces@lists.xensource.com wrote on 12/01/2005 10:03:37 PM:
> Hi All,
>     I am trying to come up with a matrix that gives the information
> about the Xen''s pages that are frequently dirtied. For this, I am
> going to use the shadow page tables. In [unstable]/arch/x86/mm.c, it
> is mentioned that these is a reference counting of pages and each
> page has two refcounts: tot_count and type_count(line No. 29 to 45).
>     But I didnt found these two refcounts being used anywhere else
> in the code. Can anybody please tell me where I can find this
> information or guide me in appropriate direction.
> Thank you very much for your time and consideration. It will be a
> great help to me,
>
> Neeta.
For each page, there are two refcounts: the usual reference count
and the type reference count.  These refcounts are defined in pfn_info
structure in xen/include/asm-x86/mm.h:

struct pfn_info *page;
page->count_info is the page reference count
page->u.inuse.type_info is the page type reference count

The page reference count is incremented and decremented in get_page()
and put_page(), respectively.  Both of these are defined in
xen/include/asm-x86/mm.h.

The page type reference count is incremented and decremented in
get_page_type() and put_page_type(), respectively.  Both of these
are defined in xen/arch/x86/mm.c.

In addition, in shadow page table mode, these reference counts
are manipulated in shadow_get_page* () and shadow_put_page* ().

Hope this helps.  Thanks.

Regards,
Khoa



_______________________________________________
Xen-devel mailing list
Xen-devel@lists.xensource.com
http://lists.xensource.com/xen-devel